Vacuum-tube-evacuating apparatus



Oct. 23, 1928.

A. A. GROTHE VACUUM TUBE EVACUATING APPARATUS Filed April 22, 1925 \N\/ENTOK RKTHUI?. R. CAROTHE RT ORNE fili PatentedOct. 23, 1928;

, f-.uNfiTfEn fsrATiEs yARTHUR A. Gnornn, or CHICAGO, ILLINOIS.

,VACUUM-Tunnfnvacimrme APPARATUS.

Appieaun lined .April 22 The present inventionrelatesto a device vfor 'determining the state of vacuum in .X-ray .andothertubea and has todo ,vvithanelectrical circuit Yassociated with ,tube baking lovens and pumping apparatus to yprevent y-dainageto the tube dnriner exhaustion.

Ineludedin the objectsy ot the invention are the following:

Means ktor .periodically` supplying energy toa tube in Athe .processoi' evacuation and means for automatically Ashutting oii Asuoli energy itits employment is dangeroustothe `tube; V y f,

.Means `for supplying;intermittently Va. prekdeterin'in,ed amount oi energyto a tube under process Eoi exhaustion combined withfseltactuated apparatusk for shortening the period of application of `such `energy Whelrdangerous to the -tnbe struc-ture;

inaitfer `aplacar are obtained by the novelv jcombination, arrangement, and construction .oithe severalvelemellts Whichgconstitute the f ,ii'iventioinoiie embodiment ofwhich is dis- Aclosed in thenccoinpanying drawing, coniprising a .schematic `rep'resentation ofrsueh Jenibodinient. s Y V lLike reference characters areused todesignate similar partsfin the drawingseandin .the description Which follows.

-Qne fornaci the ii-nvention is disclosed. L'lhis torni be termed .as semi-aut inertieV to 1 distinguish .it from another -forin whehniay be said to be automaticin its operation', which latter ,torni Yisthe subject inatterot separate application forpatent.

Beth erins oi the Vpresent invention relate to theyevaeuation of glass or other en velopesinavhich isxdisposed Yan electrode or electrodes, and while .l the description {followingy relates to the exhaustiono't X-ray tubes ot the hotcathodetype, this is butone ot the inany articlesbf current `manutacture to which the apparatus may be successfully A novel ,apparatusvtor supplying `energy*l 1925. SerialNo. 25,033.

applied. It may be employed forthe evacuation of gas X-ray tubes orgothertypesof vacuum tubesby simple niechanicaladjustment oit the various control devices.` In the radiator type of X-raytnbe, ythe `anode has a relatively large stem through which heat is dissipated with great rapidity. As previously stated, the cathode'is ofthe het lor heated type. As is yWell known in the art, the anipe'r'age of high y,tension 9.111"- hrents lwhich may pass between electrodesin aconipletely evacuated X-ray tubedepends Wholly upon the temperatureofthe cathode therein. l' .i n l .di In Figure l'representative oi ,tliewiring diagram ot the seinifautoinatic apparatus, the numeral l is used tofdesignatefan X-ray tube having an anode 2 vand a. cathode 3. Through cathode V3, mains ligand" 5 v:feed the filament a low tensioncurrent from thesec- Yondary 'of alstep-down transformer i6." The primary terminals of said transformerf are connected to the mains `marked VEilaIne'nt y line, and the source ot' electroinotivejforce yin connection therewith (butnot shownfris a means ior generating a current otconsstant voltage7 such as a storage battery yor a generator adapted toydeliver a `constant .electric pressure.l l l ln one oit' said iilalnentlinefllllins is a Aeurrfnit regulator 7 through which" theiiow ot current through cathode 3 may Abead-` Justed, thereby regulating the temperature s oiflsaidk electrode.` In evacuating ya .radiator type of tube such as isillustrated at l,`it`,lis custon'ia'ry to einploy successively threehigh tension currents l of approximately 60: k.. v. peal theiirst employed being of two miliflianiperes,..y the second et tive linillifainperes andthe thirdof ten:inilliainperes. The/reg- 'pulator 7 is therefore nranged.toperinitfof` adjustments allowing thel amperages indicatedto pass between electrodes 2 `and 3 and Aalso to hold any adjustmentinade until manually advanced to` the `next ghighern, adjustment. i

Freni the mains 8 and .9',designalted inthe Wiring .diagram `,above referredy to, as lthe Af-V-G line, the Aelectrornotive forcev .re-

.quired :for operating and controlling 4the reinainder ofthe apparatussis taken. f,

A kconduit 10 entendsy troni nlopn'eof `said mains 8,;to a relayhavingfcontact pointsill f and l2, one movable andithe other tixed. `Eroin Contact l2, acondnit 13 extendatoa later' be apparent.

control switch 14 which control switch includes a 'movable connector .15* a'dapted to engage, one at a time, contact points 16, 17

and 18. As will be noted in the drawing',` the contacts 16, 17 and 18 are ot three dii'-y ierent heights and the reason Jror this will From contact points 16,17 and 18 conduits 19, 2O and 21, respectively, are connected to a resistance 22. When the movable connector member L engagesmcontact 16 current 'passing through said member andv contact will lbe required to'passthrough; the whole of resistance 22;` when movable 'contact '15 en- "gagesfcontact 17,. the current will flow through 'lessi ot resistance22, and when said kmovable Contact 15 engages contact 18 currentJH will flow unhampe'red throughV resist-, ance y2,2,. eXcept4 tor a small amount ot fixed resistance always in the circuit. From re- `Asistan'cef22, a conduit 3 runs to one terminal of the primary of a step-up `transi'ormer '24.

A Conduit 25 connects the other terminal oit transformer 24 tommain 9 whereby a circuit betweeny mains 8 and Q and including resistance 22Y and transformer 24 is closed when contacts 11 and 12 are in engageinenty aid thegniovable connector 15 .impinges oneiot the contacts 16,17 o r 18. n 4. From one ot the terininalsot' .loftransformer 24, amain 26 runs to the anode 2 of tube v1. ,A conduit 27 from the ,otlierterminal of vthe secondary oi trans- I `former f241is connected to one terminal ot a :pairof series connected magnets 28, the other terminal ot'said paired magnets 28k beingconiiectedfby a conduit 29 to main 4 of 'the filament circuitbetween the step-down transformer 6 andthe cathode 3. Such last mentioned connection is common in the art of connecting X-rayV tubes lotfthe hot cathode type for use in photography, etc.

" ,y Conduit'27ioit the hightensioncircuit "is 'connected to main 23 or' th'exlow tension circuit, and ysaid main 23 is grounded at'231,as

or down by a standard 31,r connected thereto and .manually actuated yby movements of vcon-l nector memberf15. rlChe standard' 31 and rortatable )disc switch 14 arefs'o` associated that `when switch 14 is'rotatedfin a vlined horizon- CLI tal'plane the connector 15 thereoniengages one at a' time one ot the contacts, 16, 17, or

18, and as Vsaid contacts 16, 17, and 18 are `each ofi-aiditferent height, the standard 31 and its'appended magnets 28 are moved toi' ward or away from armature 41,`rotation of switch 14thus determining the relative position ot magnets'28 and said'armature 41.

' From', contact point 11,'a conduit 32isconf n nected 'to one terminal of the coil ot a relay 33a'ctuatingcontact 11, and from the other l "terminal of said relay coil,a conduit `34 eX- ets' 28l yare disposed Aupony a rel ciprocating standadapted to be inovedup p lessees tends toa tiltable mercury contact 35. From said mercury contact 35, a conduit'36 extends to the 'A+-C line main 9. Current willilow between lr-C line mains 8 and 9 through conduit 10, conduit 32, relay coil 33, conduit 34, mercury contact 35, and conduit 36, when the mercury contact 35 is closed. TWhen said circuit is closedas indicated, the contacts 11 and 12 will engage one another, and current will` flowfto the step-up transformer 24. The volume of such current will be regulated by theposition' of the movable contact membery 15 of the control switch 14. Gonc'urrently with such fion/,there willbe generated in the secondary of transformer 24 ahigh tension current which will pass between anode 2 and cathode`3 in tube 1, inv accordance with the temperature of cathode 3. Y f

yln "the exhaustion'v or evacuation ot' an X-ray tube and other vacuum'tubes, the vol-l ume ofthe gas in the tube decreases as the pumping ot the tube continues. With high potential current in anode2 and cathode 3 tube, being rarehed,` ionizes, establishing an electrical current flow genei'ally'of greater intensity than is sate.y 'y The electrical apparatus supplying electroinotive torce therefore ot high potential through the tube 1 when ina partly evacuated tube, the gas within the l must contain means i'orbreaking the circuit the secondary j high potential of greater magnitude thangis sai'e Aispassing between electrodes 2 and 3 otherwise a puncture therein lwill certainly occur. vin the present apparatus, a margin ot sai'ety oftwogmilliamperes has been established, so that when the intensity of the high tension current is two "or more inilliamperes abovey the-amount for whichthe device is set the circuit between mains 8 yand through transformer 2 4 will be broken. j

ln the present device, a conduit `37 extends from conduit 32 iiito'one terminalof a solenoid From the other terniinalof said 1 solenoid 38,-a conduit 39 eXtends'to a iiXed contact40 disposed: just 'above the magnets 28. -Aspring actua-ted armature 41 is connected by a conduit 42 to 'theconduit 36.

Upon each i'ace ot the armature41 is a contact point, 43 and 44,'and when the armature f i 41 is pulled down'sutticiently tar,- contact 43 thereon engages'the hiredr contact 40, `establisliing'an electrical circuit between main 8 and main 9, through the conduits 10, 32, and

40. vlilachvo the contactsl, v17 aiidr18 is adjustable.l

rlhe reason for raising and'loweringmag "moved from armature 41, the greater is the Through the center ofsolenoid 38 a slidable rod is disposed, said rod 45 being of rod 45 is thesole actuating force therefor. The ratchet associate l' v ith pinion '47 perinits it'to be rotated in a counterolocl'rfwise direction without interference with the inovein-ents of the clock inechanisin,

By this arrangement rod 45 niay be forced upwardly at any tiine, and is kept frein iininediately descending bythe pinion 47 which will allow the rod 45 to ino-ve only at a predetermined rate of speed Wholly controlled by the clock inechanisni referred to. The instant Contact isinade between fixed contact 40 and armature 4l (Contact 43), a. circuit is established through'the solenoid 38. This circuit causes the rco 45 to inove upwardly. Ordinarily, the period of engagen'ient between contacts 40 and 4S is very brief and the rod 45 would not rise the full length of its path of travel as a result of such brief inake, hence, ineans are provided whereby another circuit is established through the solenoid 38 and continued a su'llir' it tinie to carry the rod 45 to the top entieinity of' its path of nioven'ient. rlhis circuit will now be described. Y c

At the lower end of red 45 is a section 4S insulated freni the inain body ofrod by suitable insulation 49. Section 4S carries a conducting cross iiieniber 50 which is adaptA ed to engagel a pivoted Contact ii'ien'iber 5l.. Meinber- 51 comprises an arin, havingl a top flange 52 partly of conducting inaterial and partly a shoe 52 of n'on-conductin rial., and a. bottoni flange of ruin-coiniuct-v ing materia The space between flanges and 53 is coinparatively sinall and it is into this space that one end of the nien'iber 50 projects. slight impact given to rod 4,8 by tineke l; tween contacts 40 and 43' lifts the rod 45 sufficiently that the cross ineinber 50 is rais frein engagement with non-conducting flange to engageinentwith the conducting flange 52.` A circuit is thus established through conduits i0, 32 and 37, solenoid 38, conduits 39, tiltable ineinber 5l, crossiiieinber '50,rod 48 and a conduit 54 having a flexible connection with and extending yfronti rod 48 to inain 35. ln practice, it custoinaryto con nect inain 39 to tiltable ineniber 5l by a brush connection or sliding contact. Such a connection is desirable in 'hatit retard f inoveinent of nieinber 5l and nialres it neces# sary to actuate said ineinber by an external force before it iii-ay be displaced in any direction.

By tlie'circuit `inst described, the incre nient of rod 45 to its topinost position is inatesured.I kThe momentum which said rod attainsis quite great, kandthis nioinentuiiiis utilized inbrealring the circuit last referred lO. f1 'f Upon the point of flange `52^is aishoe 52 of a non-conductor, as hereinabovestated- Thelength of shoe 52 issuch that just before rod 45 reaches itstopniost point, vcross member 50 breaks contact with flange 52 and rests in engagement with vnon-conducting shoe 52a. Disengageinent between cross ineinber 50 and flange 52 breaks the lifting7 circuit, andthe nioinentuin of rod 45 is useful in rendering certain that `said cross ineinber 50 will be drawn free frein, making contact with flange 52. As the brush or sliding contactiupoir arin 51 frictionally` inaintainssaid arni against-dropping, the said arin 5l i'einains vin its.. uppermost position until external forces cause it tov travel downwardly.

Upon the rod 45 a second cross ineinbei or arni 55 which in its upward inoven'ient is adapted to tilt the inercury contact 35, brealo ing the connection lthrough the relay l33. and allowing contacts liand l2 to separate whereby electioi'notive force is shut o frein trans` fornier 24. lThe high tension current jgenerated in the secoiidaryof such transformer immediately ceases, and the tube 1 is 'saved froni overheating or puncture. l

Then the 'rod 45 has reached its uppermost position, andthe circuit through solenoid 38 is broken as has been described, ythe, rod 45 of its own weight, will begin to descend `at. a predetern'ii'ned speed controlled by the clock inechanisin of which pinion 47 is a part. As

rod 45 descends, the erossineinber or arin 55 releases the niercury contactv 35, so that the relay circuit is ire-established, causingccntacts il and l2 to iinpingeand reestablish the passage ofelectroinotive force through the transformer 24, with a concurrent production of liiglitension current passing through the tube l. It takes a predetermined tiniefor the rod 45 .totravel freni its uppermost position to its lowerinostA position. is it drops, rod 45 lalso iinpnges the flange 53 on arin 5l, and

forces it downwardly also.

lffno O'as is ionized `in tube l ,auxiliar ineans are necessary :in orc er toperiodically break the circuit throughtransformer 24 for otherwise thetube l willbecoine overl'ieated. rllhis auxiliary ineans for establishing a circuit through the solenoid 38 comprises a inercury contact 5G oneend of which engages the conduit 57 flexiblyconnected to rod 48.` Ars t-lie rod 45 travels downwardly until it closely approaches its lowerinost point of travel, arin 50 engages the ii'iercury contact 56 and tilts it toestablish `a circuit fro-ni conduitk 39 through contact 56 conduit 57, rod 48 and conduit `54. The connections inthe circuit just describedY and the A-G line mains 8 and` 9 recited in detail coinprise the followingrconduits110,32 and 37, solenoid 38, conduit 39, niercury con- Cil tact 56, conduit 57, rod; 48, and conduits 54' and 36. This fi'nalre gives to rod 45 an impulse causingcross nieniberr() to impinge tlange 52, producing the liiting7 circuit for tube 1 may be had. For radiator typesoic tubes, the. heat oie tlieitube is suii'icientlydisf sipated to prevent overheating `it the, OHV and -oii7 periods, alteriiately'occurring, `are of iifteenseconds duration. The automaticiea,4

vtures of the device shorten the on period itl danger appears, but `the toftperiods remain at fifteen Seconds due to the clockvvorks re- Aterred'to hereinabove. l l

A specially Wound, constant voltage, A. C. generator, driven by a synchronous motor, is

usedto vsupply currentito the filament line with excel-lent results. .In the Wiring diagrams it Will be noted that the ilanient circuit is on the groundedside;` hence, no provision for high voltage insulation bet'iveen tlieprimary and secondaryof the filament trans-M iormer would be necessary Were the device to Ybe always used aloneg rBut it is sometimes necessary to coniiectthetube 1 to a trans- `former delivering al voltage of .about 130 k. v.

(peak) in Which event, an insulated ilament Winding is necessary. f Having the filament circuit on the grounded sidealso .simplifies the circuit. c

Condensers 58 are connected in the circuit to prevent sparking between windings of the magnets 28 and the stand -30 and standard 31.

'It such condenseis are not in circuit, the high 'frequency currents generated Wheneverfgas appearsl in tube 1 Will tend to Jump to the stand 3() and` standard 31k instead of going'y through the coils.k Under suchconditions, the

armature41 will not be attracted to the` contact'40. The current will continue to flow in the tube 1, and if sutticient gas is generated.; the tube 1 will be puiictured. Said condensers 58- are connected in yseries in the high tension circuit and grounded atthe center to standard 31. Acondenser 59 is connected across armai ture 41 and contact 40to reduce sparking., y yA 'non-inductive' resistance surge arrester 60 grounded at its centeris connected across the Winding yof solenoid 38, to prevent the iviiiding'thereot from being punctured due to high requencysurges produced in the primary circuit. y Similar arresters 61 and 62 are placed: across the relay Winding B3 and the primary Winding of the transformer 24.;

4Should the current in tube 1 be deficient with respect toits intensity, a visual signal is provided. The deiiciency` to operate said signal is approximately two milliamperes or more. 1 Y

, develops.

to reduce vibration, hence movesonly under This pre- Y duit 10, contacts ,11 and 12, conduit 64, con-v tacts and 44, and conduit 42.` f frs previously indicated, armature 41 is spring aactuated. The adjustment-of the `spring (not shown) is suoli that said armature contact 44 normally rests against contact 68. The passing of current of proper intensity through magnets 28 causes said mag.-

nets 28 to pull r,armature 41 into a neutral position intermediate contacts 40 `and 6,8. The armature 28 remains in such neutral position so long asa proper current flows in ther liiOli tension circuit, but the contacts thereon, 48l and 44, will move into engagement with contacts 40 or respectively, when an excess n or an insuniciency ot' high tension current ii'iiiature 4l is heavily vWeighted the iiilluence ci a positive `torce. n vents vibrating makes between contacts 40 and and contacts 44 and 63,.

l A manually actuated spring releasesvvitch 66 may be inserted betweenconduits 13 and 37 to provide for establishing high tension current irrespective or the position of the re-k Withy a; vacuum tube ien during evacuation comprising means` for'y periodically supplying a volume Yof energy thereto, means responding to an excess of energy in said tube for terminating such energy supply'vvhen lits volume becomes excessive, and manually controlled means for increasing said volume of energy as evacuation of the tube progresses. i

2. A device to be emplcyed With a vacuum tube during evacuation comprising means for periodically supplying afpredetermined volunie Voi energy thereto, means responding to an excess of energyin said tube for terminating such energy supply vvhenits volumehas become' excessive, andl manually controlled means for increasing lsaid volumev of energy as evacuation rof said tube progresses, and in predetermined kllo which said energy .suppiying and terminating l means comprises a 4time actuated relay.

3. Thel combination Withacircuitifor supplying energy` to a vacuum tube Vduring .evacuation comprising a main line to a stepup transformer, a high tension line from said transformer to saidy tube, a timeactuated relayV automatically terminatingA the admission oit-energy to saidtube, and manually controlled means for increasing the volume of energy admitted to said tube, of an armature movable in one direction to actuatel said energy terminating means, and a signal iso i adapted to be actuated when said armature is moved in another direction.

Il. The combination with a circuit for supplying energy to a vacuum tube during evacuation comprising a main line to a stepup transformer, a high tension line from ysaid transformer to said tube, a time actuated relay automatically terminating the admission of energyk to said tube, a signal for indicating increase in the vacuum in said tube, and manually controlled means for increasing the volume of energy admitted to said tube, of an armature adapted to be actuated by the energy flowing through said tube to control said means for terminating the iiow of current to said tube.

5. ln a tube evacuating apparatus, a low tension circuit to a transformer, a high ten` sion circuit from said transformer, a magnet in said high tension circuit, a spring actuated armature disposed within the influence of said. magnet, a. relay adapted to be actuated by said armature when moved in one direction and opening said low tension circuit, and manually controlled means for sepaating said magnet and armature.

6. The apparatus described in claim 5, and in which relative movement of said magnet and arn'iature regulate the volume of energy which may flow in said high tension circuit.

7. The apparatus described in claim 5, in

combination with a visual signal adapted to be actuated by said armature when moved in the opposite direction.

8. For supplying electromotive force to a vessel in process of evacuation, a circuit comprising a relay, and contacts actuated by an armature for operating said relay, in com-v bination with a magnet for actuating said armature, and means for manually determin-` ing the relative position of said magnet and said armature.

9. For supplying electromotive force to a vessel in process of evacuation, a circuit comprising a relay, and contacts actuated by an armature for operating said relay, in combination with a magnet for actuating said armature, and means for manually separating said magnet and said armature a. plurality of predetermined distances.

10. In combination, a low tension circuit to a transformer and having a resistance and a relay therein, a high tension circuit from said transformer to a tube in process of evacuation, a magnet in said high tension circuit, a base for said magnet and adjust-ably mounted, an armature in juxtaposition to said magnet and adapted to close the circuit to said relay, and a switch member for eliminating resistance in said low tension circuit, actuation of said switch member being adapted to modify the relative position of said magnet base to said armature.

11. In combination, a low tension circuit to a transformer and having a resistance and a relay therein, a high tension circuit from 1 said transformer to a tube in process of evacuation, a magnet in said high tension circuit,

Va base for said magnet andadjustably mounted, an armature in juxtaposition to said magnet and adapted to close the circuit to said relay, and a switch member for eliminating resistance in said low tension circuit, actuation of said switch member being adapted to modify the relative position of said base to said armature, and in which said magnet ybase has a plurality of adjustments coinciding with the points upon said resistance switch.

12. Ink combination, a low tension circuit to a transformer and having a resistance and a relay therein, a high tension circuit from said transformer toa tube in process of evacuation, a magnet in said high tension circuit, a base for said magnet and adj ustably mount ed, an armature in juxtaposition to said magnet andadapted to close the circuit to said relay, and a switch member for eliminating resistance in said low tension circuit, actuation of said switch member being adapted to modify the relative position of said magnet base to said armature, said magnet base having a cam surface adapted to be engaged by said handle for adjusting the magnet on said base relatively to said armature.

ARTHUR A. GROTHE. 

